U.S. Pat. No. 4,467,927 issued Aug. 28, 1984 discloses and claims a molded tray for display stands and includes one form of socket at each corner which is retained within the confines of the periphery of the shelves.
U.S. Pat. No. 4,550,838 issued Nov. 5, 1985 discloses a modular display rack in which apertures are formed in the side walls of the rack shelves for receiving support rods which are disposed in angular relation to an imaginary vertical plane.
U.S. Pat. No. 4,690,287 issued Sept. 1, 1987 and owned by the assignee of this invention discloses a display device in which one shelf is disposed above another and supported by means of U-shaped brackets which are interrelated with the two vertically spaced units so as to hold such units in spaced relation.
U.S. Pat. No. 4,763,796 issued Aug. 16, 1988 discloses a display arrangement wherein sockets of square or rectangular configuration are arranged to cooperate with vertically disposed posts which are of square or of rectangular configuration.